 /* crypto/bn/bn_prime.c */

 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 * 

 * This library is free for commercial and non-commercial use as CrLONG32 as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 * 

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 * 

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from 

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 * 

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 * 

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */



#include "crypto/CrBNConfig.h"

#ifdef _BN_PRIME_C



//#include <stdio.h> // for NULL

////#include <time.h>

//#include "crypto/cryptlib.h"

#include "crypto/CrBN.h"

#include "crypto/CrBNLcl.h"

#include "crypto/CrRand.h"





 /* The quick seive algorithm approach to weeding out primes is

 * Philip Zimmermann's, as implemented in PGP.  I have had a read of

 * his comments and implemented my own version.

 */

#include "crypto/CrBNPrime.h"



#ifndef NOPROTO

static CrINT32 witness(BIGNUM *a, BIGNUM *n, BN_CTX *ctx,BN_CTX *ctx2,

	BN_MONT_CTX *mont);

static CrINT32 probable_prime(BIGNUM *rnd, CrINT32 bits);

static CrINT32 probable_prime_dh(BIGNUM *rnd, CrINT32 bits,

	BIGNUM *add, BIGNUM *rem, BN_CTX *ctx);

static CrINT32 probable_prime_dh_strong(BIGNUM *rnd, CrINT32 bits,

	BIGNUM *add, BIGNUM *rem, BN_CTX *ctx);

#else

static CrINT32 witness();

static CrINT32 probable_prime();

static CrINT32 probable_prime_dh();

static CrINT32 probable_prime_dh_strong();

#endif

BIGNUM*		BN_generate_prime(CrINT32 bits,CrINT32 strong,BIGNUM *add,

							BIGNUM *rem,void (*callback)(CrINT32,CrINT32,CrINT8 *),CrINT8 *cb_arg);



BIGNUM *BN_generate_prime(

CrINT32 bits,

CrINT32 strong,

BIGNUM *add,

BIGNUM *rem,

void (*callback)(P_I_I_P),

CrINT8 *cb_arg)

{

	BIGNUM *rnd=NULL;

	BIGNUM *ret=NULL;

	BIGNUM *t=NULL;

	CrINT32 i,j,c1=0;

	BN_CTX *ctx;





	ctx=BN_CTX_new();

	if (ctx == NULL) goto err;

	if ((rnd=BN_new()) == NULL) goto err;

	if (strong)

		if ((t=BN_new()) == NULL) goto err;

loop: 

	 /* make a random number and set the top and bottom bits */

	if (add == NULL)

		{

		if (!probable_prime(rnd,bits)) goto err;



		}

	else

		{

		if (strong)

			{

			if (!probable_prime_dh_strong(rnd,bits,add,rem,ctx))

				 goto err;

			}

		else

			{

			if (!probable_prime_dh(rnd,bits,add,rem,ctx))

				goto err;

			}



		}

	 /* if (BN_mod_word(rnd,(BN_ULONG)3) == 1) goto loop; */

	if (callback != NULL) callback(0,c1++,cb_arg);



	if (!strong)

	{



		i=BN_is_prime(rnd,BN_prime_checks,callback,ctx,cb_arg);



		if (i == -1) goto err;

		if (i == 0) goto loop;

	}

	else

	{

		 /* for a strong prime generation,

		 * check that (p-1)/2 is prime.

		 * Since a prime is odd, We just

		 * need to divide by 2 */

		if (!BN_rshift1(t,rnd)) goto err;



		for (i=0; i<BN_prime_checks; i++)

		{

			j=BN_is_prime(rnd,1,callback,ctx,cb_arg);



			if (j == -1) goto err;

			if (j == 0) goto loop;



			j=BN_is_prime(t,1,callback,ctx,cb_arg);



			if (j == -1) goto err;

			if (j == 0) goto loop;



			if (callback != NULL) callback(2,c1-1,cb_arg);

			 /* We have a strong prime test pass */

		}



	}

	 /* we have a prime :-) */

	ret=rnd;

err:

	if ((ret == NULL) && (rnd != NULL)) BN_free(rnd);

	if (t != NULL) BN_free(t);

	if (ctx != NULL) BN_CTX_free(ctx);



	return(ret);

	}



CrINT32 BN_is_prime(

BIGNUM *a,

CrINT32 checks,

void (*callback)(P_I_I_P),

BN_CTX *ctx_passed,

CrINT8 *cb_arg)

	{

	CrINT32 i,j,c2=0,ret= -1;

	BIGNUM *check;

	BN_CTX *ctx=NULL,*ctx2=NULL;

	BN_MONT_CTX *mont=NULL;





	if (!BN_is_odd(a))

		return(0);

	if (ctx_passed != NULL)

		ctx=ctx_passed;

	else

		if ((ctx=BN_CTX_new()) == NULL) goto err;



	if ((ctx2=BN_CTX_new()) == NULL) goto err;



	if ((mont=BN_MONT_CTX_new()) == NULL) goto err;





	check=ctx->bn[ctx->tos++];



	 /* Setup the montgomery structure */

	if (!BN_MONT_CTX_set(mont,a,ctx2)) goto err;



	for (i=0; i<checks; i++)

		{

		if (!BN_rand(check,BN_num_bits(a)-1,0,0)) goto err;

		j=witness(check,a,ctx,ctx2,mont);

		if (j == -1) goto err;

		if (j)

			{

			ret=0;

			goto err;

			}

		if (callback != NULL) callback(1,c2++,cb_arg);

		}

	ret=1;



err:

	ctx->tos--;

	if ((ctx_passed == NULL) && (ctx != NULL))

		BN_CTX_free(ctx);

	if (ctx2 != NULL)

		BN_CTX_free(ctx2);

	if (mont != NULL) BN_MONT_CTX_free(mont);



	return(ret);

	}



#define RECP_MUL_MOD



static CrINT32 witness(

BIGNUM *a,

BIGNUM *n,

BN_CTX *ctx,

BN_CTX *ctx2,

BN_MONT_CTX *mont)

	{

	CrINT32 k,i,ret= -1,good;

	BIGNUM *d,*dd,*tmp,*d1,*d2,*n1;

	BIGNUM *mont_one,*mont_n1,*mont_a;



	d1=ctx->bn[ctx->tos];

	d2=ctx->bn[ctx->tos+1];

	n1=ctx->bn[ctx->tos+2];

	ctx->tos+=3;



	mont_one=ctx2->bn[ctx2->tos];

	mont_n1=ctx2->bn[ctx2->tos+1];

	mont_a=ctx2->bn[ctx2->tos+2];

	ctx2->tos+=3;



	d=d1;

	dd=d2;

	if (!BN_one(d)) goto err;

	if (!BN_sub(n1,n,d)) goto err;  /* n1=n-1; */

	k=BN_num_bits(n1);



	if (!BN_to_montgomery(mont_one,BN_value_one(),mont,ctx2)) goto err;

	if (!BN_to_montgomery(mont_n1,n1,mont,ctx2)) goto err;

	if (!BN_to_montgomery(mont_a,a,mont,ctx2)) goto err;



	BN_copy(d,mont_one);

	for (i=k-1; i>=0; i--)

		{

		if (	(BN_cmp(d,mont_one) != 0) &&

			(BN_cmp(d,mont_n1) != 0))

			good=1;

		else

			good=0;



		BN_mod_mul_montgomery(dd,d,d,mont,ctx2);

		

		if (good && (BN_cmp(dd,mont_one) == 0))

			{

			ret=1;

			goto err;

			}

		if (BN_is_bit_set(n1,i))

			{

			BN_mod_mul_montgomery(d,dd,mont_a,mont,ctx2);

			}

		else

			{

			tmp=d;

			d=dd;

			dd=tmp;

			}

		}

	if (BN_cmp(d,mont_one) == 0)

		i=0;

	else	i=1;

	ret=i;

err:

	ctx->tos-=3;

	ctx2->tos-=3;

	return(ret);

	}



static CrINT32 probable_prime(BIGNUM *rnd, CrINT32 bits)

	{

	CrINT32 i;

//	MS_STATIC BN_ULONG mods[NUMPRIMES];

	static BN_ULONG mods[NUMPRIMES];

	BN_ULONG delta;



	if (!BN_rand(rnd,bits,1,1)) return(0);

	 /* we now have a random number 'rand' to test. */

	for (i=1; i<NUMPRIMES; i++)

		mods[i]=BN_mod_word(rnd,(BN_ULONG)primes[i]);

	delta=0;

	loop: for (i=1; i<NUMPRIMES; i++)

		{

		 /* check that rnd is not a prime and also

		 * that gcd(rnd-1,primes) == 1 (except for 2) */

		if (((mods[i]+delta)%primes[i]) <= 1)

			{

			delta+=2;

			 /* perhaps need to check for overflow of

			 * delta (but delta can be upto 2^32) */

			goto loop;

			}

		}

	if (!BN_add_word(rnd,delta)) return(0);

	return(1);

	}



static CrINT32 probable_prime_dh(

BIGNUM *rnd,

CrINT32 bits,

BIGNUM *add,

BIGNUM *rem,

BN_CTX *ctx)

	{

	CrINT32 i,ret=0;

	BIGNUM *t1;



	t1=ctx->bn[ctx->tos++];



	if (!BN_rand(rnd,bits,0,1)) goto err;



	 /* we need ((rnd-rem) % add) == 0 */



	if (!BN_mod(t1,rnd,add,ctx)) goto err;

	if (!BN_sub(rnd,rnd,t1)) goto err;

	if (rem == NULL)

		{ if (!BN_add_word(rnd,1)) goto err; }

	else

		{ if (!BN_add(rnd,rnd,rem)) goto err; }



	 /* we now have a random number 'rand' to test. */



	loop: for (i=1; i<NUMPRIMES; i++)

		{

		 /* check that rnd is a prime */

		if (BN_mod_word(rnd,(BN_LONG)primes[i]) <= 1)

			{

			if (!BN_add(rnd,rnd,add)) goto err;

			goto loop;

			}

		}

	ret=1;

err:

	ctx->tos--;

	return(ret);

	}



static CrINT32 probable_prime_dh_strong(

BIGNUM *p,

CrINT32 bits,

BIGNUM *padd,

BIGNUM *rem,

BN_CTX *ctx)

	{

	CrINT32 i,ret=0;

	BIGNUM *t1,*qadd=NULL,*q=NULL;



	bits--;

	t1=ctx->bn[ctx->tos++];

	q=ctx->bn[ctx->tos++];

	qadd=ctx->bn[ctx->tos++];



	if (!BN_rshift1(qadd,padd)) goto err;

		

	if (!BN_rand(q,bits,0,1)) goto err;



	 /* we need ((rnd-rem) % add) == 0 */

	if (!BN_mod(t1,q,qadd,ctx)) goto err;

	if (!BN_sub(q,q,t1)) goto err;

	if (rem == NULL)

		{ if (!BN_add_word(q,1)) goto err; }

	else

		{

		if (!BN_rshift1(t1,rem)) goto err;

		if (!BN_add(q,q,t1)) goto err;

		}



	 /* we now have a random number 'rand' to test. */

	if (!BN_lshift1(p,q)) goto err;

	if (!BN_add_word(p,1)) goto err;



	loop: for (i=1; i<NUMPRIMES; i++)

		{

		 /* check that p and q are prime */

		 /* check that for p and q

		 * gcd(p-1,primes) == 1 (except for 2) */

		if (	(BN_mod_word(p,(BN_LONG)primes[i]) == 0) ||

			(BN_mod_word(q,(BN_LONG)primes[i]) == 0))

			{

			if (!BN_add(p,p,padd)) goto err;

			if (!BN_add(q,q,qadd)) goto err;

			goto loop;

			}

		}

	ret=1;

err:

	ctx->tos-=3;

	return(ret);

	}



#if 0

static CrINT32 witness(

BIGNUM *a,

BIGNUM *n,

BN_CTX *ctx)

	{

	CrINT32 k,i,nb,ret= -1;

	BIGNUM *d,*dd,*tmp;

	BIGNUM *d1,*d2,*x,*n1,*inv;



	d1=ctx->bn[ctx->tos];

	d2=ctx->bn[ctx->tos+1];

	x=ctx->bn[ctx->tos+2];

	n1=ctx->bn[ctx->tos+3];

	inv=ctx->bn[ctx->tos+4];

	ctx->tos+=5;



	d=d1;

	dd=d2;

	if (!BN_one(d)) goto err;

	if (!BN_sub(n1,n,d)) goto err;  /* n1=n-1; */

	k=BN_num_bits(n1);



	 /* i=BN_num_bits(n); */

#ifdef RECP_MUL_MOD

	nb=BN_reciprocal(inv,n,ctx);  /**/

	if (nb == -1) goto err;

#endif



	for (i=k-1; i>=0; i--)

		{

		if (BN_copy(x,d) == NULL) goto err;

#ifndef RECP_MUL_MOD

		if (!BN_mod_mul(dd,d,d,n,ctx)) goto err;

#else

		if (!BN_mod_mul_reciprocal(dd,d,d,n,inv,nb,ctx)) goto err;

#endif

		if (	BN_is_one(dd) &&

			!BN_is_one(x) &&

			(BN_cmp(x,n1) != 0))

			{

			ret=1;

			goto err;

			}

		if (BN_is_bit_set(n1,i))

			{

#ifndef RECP_MUL_MOD

			if (!BN_mod_mul(d,dd,a,n,ctx)) goto err;

#else

			if (!BN_mod_mul_reciprocal(d,dd,a,n,inv,nb,ctx)) goto err; 

#endif

			}

		else

			{

			tmp=d;

			d=dd;

			dd=tmp;

			}

		}

	if (BN_is_one(d))

		i=0;

	else	i=1;

	ret=i;

err:

	ctx->tos-=5;

	return(ret);

	}

#endif



#endif //end of #ifdef _BN_PRIME_C


